This invention relates to devices and methods for treating distal radius fractures.
Distal radius fractures are among the most common type of bone fracture of the upper extremities. The distal radius fracture is often called a xe2x80x9cCollesxe2x80x9d fracture (named after a 19th Century British surgeon who described the fracture). The Colles fracture is associated with a fracture of a distal tip or distal end portion of the radius.
Distal radius fractures are, unfortunately, most common in the elderly segment of the population. This is because the elderly tend to exhibit some degree of bone density loss or osteoporotic condition making their bones more susceptible to injury. Indeed, just as osteoporosis is known to affect women more often and more severely than men, distal radius fractures are much more common in females than males, typically on the order of about 20:1. Distal radius fractures generally occur as a result of a fall, because the patient tends to brace for the fall by outstretching the hand which then fractures upon impact, at the distal radius at or adjacent the wrist.
As shown in FIGS. 1 and 2, the distal radius fracture is such that the major fracture line 15 associated with this type of injury generally occurs just above or proximal to the articular joint surface 11 of the distal radius at the wrist about the metaphysis 12. As shown in FIGS. 1 and 2, one common distal radius fracture type separates the shaft 13 of the radius 10 from the distal end portion of the bone. That is, the fracture line 15 defines a first major bone fragment 18 which is located distal to the fracture line 15 proximate the articular joint surface 11 and extends substantially medially (laterally) across the radius 10 in the metaphysis region. Although not shown, the fracture may also produce smaller bone fragments or splinters along the fracture line. Further, the distal end portion of the radius may be present as multiple (vertically and/or horizontally oriented) fragments disrupting the articular joint surface itself. This latter type of Colles fracture is known as a comminuted intraarticular fracture (not shown).
FIG. 1 illustrates the fracture line 15 in the radius 10 as a substantially horizontal line which produces an upper or distal fracture fragment 18 as a substantially unitary fragment. Similarly, FIG. 2 illustrates a fracture line 15 in the radius 10 which is offset from a horizontal axis.
Distal radius fractures can be difficult to treat, particularly in the older osteoporotic patient. Conventionally, this type of fracture has been treated by a closed (non-surgical) reduction and application of a splint (such as a plaster compression dressing) or a cast (typically circular plaster or fiberglass). Unfortunately, primarily because of the patient""s osteoporosis, during the healing process, and despite the splint/cast immobilization, the fracture fragments can settle, potentially causing a collapse at the fracture line in the distal radius. FIG. 2 illustrates a loss of radial inclination (in degrees) and a shortened length in the skeletal length line (shown with respect to a neutral length line xe2x80x9cLxe2x80x9d) which can occur after a fracture in the distal radius. That is, even healed, these types of fractures may cause shortening or collapse of the bone structure relative to the original skeletal length line. This, in turn, can result in deformity and pain.
Treatment options for a collapsed distal radius fracture are relatively limited. The primary conventional treatments include the use of devices which can be characterized as either external fixation devices or internal fixation devices. External fixation devices are those that stabilize a fracture through the use of percutaneous pins which typically affix one or more bone portions to an external (anchoring or stabilizing) device. Internal fixation devices are those devices which are configured to reside entirely within the subject (internal to the body). Percutaneous pins can be used alone, without anchoring devices, for fixation of Colles type fractures. The use of external devices has conventionally been thought to be particularly indicated in cases of bone loss to preserve skeletal length as noted, for example, in U.S. Pat. No. 5,571,103 to Bailey at col. 1, lines 35-43. However, such devices can be bulky, cumbersome, and or invasive to the user or patient. Further, the external fixation devices may not be suitable for use in soft osteoporotic bone.
In view of the foregoing, there remains a need for improved distal radius fracture treatment devices and techniques.
In a preferred embodiment, the present invention provides methods and devices for treating fractures in or adjacent the wrist and distal forearm. The present invention is particularly useful for stabilizing and treating distal radius fractures of a patient. The devices and methods of the present invention employs an intramedullary interlocking fixation rod (i.e, it interlocks the distal and proximal fracture fragments together) to stabilize the skeletal structure in a manner which can inhibit the amount of collapse or loss in skeletal length exhibited by a patient with a distal radius fracture. The devices and methods of the present invention may be especially useful for treating distal radius fractures in subjects with osteoporosis.
One aspect of the invention is a method for treating a distal radius fracture of a patient comprising the use of an internal fixation rod. As noted above, the radius anatomically has an articular joint surface, a metaphysis region, a shaft portion and a medullary canal associated therewith. The distal radius fracture has a fracture line which divides the radius into a distal fracture fragment portion and a proximal fracture fragment portion. The distal fragment portion includes the distal end of the radius proximate the articular joint surface, and the distal portion of the fracture has a width thereacross. The method comprises the steps of: (a) installing an elongated rod having opposing proximal and distal portions into the medullary canal of the patient such that the proximal portion of the rod resides above the fracture line (closer to the elbow) and the distal portion of the rod resides below the fracture line (closer to the hand); (b) securing a distal fixation member to the elongated rod and into the distal end portion of the radius at a location which is below the fracture line such that the distal fixation member extends internal of the patient substantially laterally across a portion of the width of the distal fracture fragment; and (c) anchoring the elongated rod inside the medullary canal of the radius at a location which is above (distal to) the fracture line.
Another aspect of the present invention is an internal fixation device for treating or repairing distal radius fractures having a fracture line forming distal and proximal fracture fragments. The radius is anatomically configured with a distal articular joint surface, a metaphysis region, a shaft, and a medullary canal. The anatomic position of the hand is palm forward or front such that the medial orientation is next to the body (fifth finger or ulna side of hand) and the lateral orientation is away from the body (thumb or radial side). Generally stated, the distal portion of the radius has a width which extends across (a major portion of) the arm from the medial side to the lateral side. The device includes an elongated fixation rod having opposing proximal and distal portions. The distal portion includes a head with a laterally extending distal aperture formed therein, and the proximal portion comprises at least one proximal aperture formed therein. The elongated fixation rod proximal portion is sized and configured such that, in position, it resides in the shaft inside a portion of the medullary canal of the radius of a patient. The device also includes a distal fixation member configured to enter the distal aperture and attach to the rod and the distal fracture fragment to hold the distal portion of the rod to the distal fracture fragment. The device further includes at least one proximal fixation member, a respective one for each of the at least one proximal apertures. The proximal fixation member is configured to secure the lower portion of the fixation rod to the radius at a position which is distal to the fracture line. In position, the elongated fixation rod is configured to reside within the radius, and the distal fixation member and the at least one proximal fixation member are configured to reside internal of the body of the patient.
In a preferred embodiment, the elongated fixation rod has a curvilinear profile. The curvilinear profile includes a distal curve portion at the distal portion of the device. The distal curve portion is adapted to accommodate the radial styloid region of the radius proximate the articular joint surface. The rod can also be provided as a plurality of segments matable or attachable. In one embodiment an intermediate segment can be provided in different lengths to allow for the adjustment of length according to a patient""s anatomical considerations. Of course, the rod can be a unitary body provided in a number of standard sizes preferably statistically representative of the treatment population.
The foregoing and other objects and aspects of the present invention are explained in detail in the specification set forth below.